如何自動調整單元格大小以適合每行4行

Question

我有一個集合視圖，我正在尋找一種方法來查明單元格的大小可以適合每行4個單元格（在特定的屏幕大小上）並使用在所有單元格上的大小。我有一個可重用的單元格，用於其他單元格。

Answer 1

extension LevelSelectController: UICollectionViewDelegateFlowLayout { 

// Collection view flow layout setup 
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { 
    // Compute the dimension of a cell for an NxN layout with space S between 
    // cells. Take the collection view's width, subtract (N-1)*S points for 
    // the spaces between the cells, and then divide by N to find the final 
    // dimension for the cell's width and height. 

    let cellsAcross: CGFloat = 4 
    let spaceBetweenCells: CGFloat = 0 
    let dim = (collectionView.bounds.width - (cellsAcross - 1) * spaceBetweenCells)/cellsAcross 

    return CGSize(width: dim, height: dim) 
} 

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets { 
    return UIEdgeInsetsMake(0, 0, 0.0, 0.0) 
} 

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat { 
    return 0.0 
} 

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat { 
    return 0.0 
}